Báo cáo khoa học: Hydrogels as Drug Delivery Systems (Hệ dẫn truyền thuốc Hydogels)

SEMINAR REPORT OF DRUG DELIVERY SYSTEMS

Topic: Hydrogels as Drug Delivery Systems Reporter:

Nguyen Van Tu

Supervisor:

Dr. Le Thanh Dung Dr. Ha Cam Anh

- 51305919

HCM city, October, 2014

HOOK INTRODUCTION

Various Systems to be applied

Attract much attention

DDSs

Hydrogels: worth concerning

Each System possesses particular characteristics DDSs: Drug Delivery Systems

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SOME FIGURES

The total number of papers on hydrogels from 1950 to 2011 was 43 764. Of these, 8554 references were on the topic of drug delivery. In the drug delivery topic, the search for subtopics of proteins and genes resulted in 1674 and 284 references, respectively.

- S. C. Lee, I. K. Kwon and K. Park, Adv. Drug Delivery Rev., 2013,65,17–20

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OUTLINE 1- GENERALITIES OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS 2- STRUCTURES OF HYDROGELS – TOWARDS BEING USED 3- THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

4- MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS 5- POSIBILITIES OF APPLICATION 6- INCLUSION 4

I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.1. What is gel?  Coined by 19th-century Scottish

Chemist Thomas Graham  is a solid, jelly-like material that

can have properties ranging from soft and weak to hard and tough.  Gels are defined as a cross-linking

system, which exhibits no flow when in the steady-state.  By weight, gels are mostly liquid, yet they behave like

solids due to a three-dimensional cross-linked network within the liquid. http://en.wikipedia.org/wiki/Gel

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.1. What is gel?  The solid is the continuous phase and the liquid is

the discontinuous phase.

http://en.wikipedia.org/wiki/Gel

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.2. What is hydrogel?  Is a Gel in which the swelling agent

is water (water is discontinuous phase).  The network component of a

hydrogel is usually a polymer network.  A hydrogel in which

the network component is a colloidal network may be referred to as an Aquagel.

http://en.wikipedia.org/wiki/Gel http://www.gcsescience.com/o70.htm

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.2. What is hydrogel?  A hydrogel is an example of

a smart material.  It can change structure in

response to salt concentration, pH and temperature.

http://en.wikipedia.org/wiki/Gel http://www.gcsescience.com/o70.htm

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.2. What is hydrogel?  Hydrogels are 3D hydrophilic macromolecular networks

(matrices) that are capable of retaining a large amount of water.  Having been used in a variety of applications, such as wound

dressings, transdermal patches, drug delivery devices, contact lenses, or in reconstructive surgery.

Repeating unit of LBG, Xanth, and a photograph of the obtained physical gel.

- European Biophysics Journal 2007. Vol: 36(7):693-700. DOI: 10.1007/s00249-007-0158-y - Expert Rev Med Devices. 4(2), 147-164 (2007). DOI: 10.1586/17434440.4.2.147

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.3. Major definitions  Cross-link

- A cross-link is a bond that links one polymer chain to another. They can be covalent bonds or ionic bonds…

"Polymer chains" can refer to synthetic polymers or natural polymers .

Cross-links

- http://en.wikipedia.org/wiki/Cross-link

Vulcanization with sulfur 10

I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.3. Major definitions  Swelling and deswelling

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.3. Major definitions  Swelling and deswelling

- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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I. VIEW OF GELS AND HYDROGELS – FUNDAMENTAL CONCEPTIONS

1.4. Hydrogels classification Classification

Contents

Classification

Contents

Origin

-

Natural Synthetic

Cross-linking method

-

Chemical (or covalent) Physical (or noncovalent)

Ionic charge (based on the nature of the pendent groups)

-

Neutral Anionic Cationic Ampholytic

Component (based on the method of preparation)

-

Homopolymer Copolymer Multipolymer Interpenetrating

-

Low swelling Medium swelling High swelling Superabsorbent

Function (based on the organization of the monomers) -

-

Nonporous Microporous Macroporous Superporous

Mechanism controlling the drug release

Water content of degree of swelling

Network Structure (porosity)

- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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Biodegradable or Nonbiodegradable Stimuli responsive Superabsorbent Diffusion Swelling Chemically controlled Environment responsive

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.1. Structures  Hydrogels are cross-linked polymers that

have hydrophillic groups (-OH, -COOH, -CONH2, - SO3H, etc).

Absence of Na+ ion (remove all salts)

- http://www.gcsescience.com/o70.htm

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.1. Structures

Water molecules are attracted to the negative charges by hydrogen bonding - http://www.gcsescience.com/o70.htm

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.1. Structures

-, Journal of Microelectromechanical Systems. Vol.11, No.5, October 2002 16

II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.1. Structures - Hydrophilic domains are present, which are hydrated in a aquaous environment, creating the hydrogel structure.

- Crosslinks prevent complete mixing of the polymer chains and the aquaous phase by providing an elastic restoring force that counters the expansion of the network.

- Journal of Microelectromechanical Systems. Vol.11, No.5, October 2002 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.2. Properties to orient to applications Biocompatibility Biodegradability

Requirements

Tunable charateristics Balance between mechanical and degradation properties Adaptability to commonly used sterilization procedures (implantable systems)

- Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.2. Properties to orient to applications * Biocompatibility

- Hydrogels resemble natural living tissue more than any other class of synthetic biomaterials due to their high water content and soft consistency which is similar to natural tissue.

- Hydrogels are polymeric materials that do not dissolve in water in physiological conditions.

- Anti toxicity.

- Advanced Drug Delivery Reviews, 11 (1993) 59-84.

- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-19.9 - Journal of Materials Chemistry B, 2014, 2, 147-166.

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.2. Properties to orient to applications ** Biodegradability

- The degradation processes leading to the formation of subspecies should take place without any side effects.

- The removal of the anticipated by-products from the body should be given consideration before the actual formulation of these systems.

-The degradation products can be removed by excretory pathways.

- Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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II. STRUCTURES OF HYDROGELS – TOWARDS BEING USED

2.2. Properties to orient to applications *** Tunable characteristics

- Tunable network structure to control the diffusion of drugs and tunable affinity for drugs.

- Invironment responsive hydrogels for release drugs (pH, temperature, light, glucose, antigen, ionic strength, etc).

- Advanced Drug Delivery Reviews, 11 (1993) 59-84 - Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels

Hydrogels Natural hydrogels

Synthetic hydrogels

Natural polymers

Synthetic polymers

Cross-linking physical bonds

Cross-linking chemical bonds

- Journal of Biomaterials and Nanobiotechnology. 2012, 3, 185-199 - Progress in Polymer Science. Vol 32, No.7, 2007, pp.669–697

Cross-linking polymerization of Synthetic Monomers 22

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels

ï‚— Especially,

Natural hydrogels

Synthetic hydrogels

Hydrogels with particular properties - Advanced Drug Delivery Reviews, Vol. 11, No. 1-2, 1993, pp. 59-84 - Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.1. Physical cross-linking

Hydrogels obtained are called physical gels or reversible gels

Properties

Easy to production The advantage of not using cross-linking agents

- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.1. Physical cross-linking

Heating/cooling a polymer solution Ionic interaction Complex coacervation

Means H-bonding Maturation (heat induced aggregation)

Freeze-thawing - Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.1. Physical cross-linking

CMC

H-bonding

- Transactions of the Materials Research Society of Japan, Vol 32, No 332, 713-716 26

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.1. Physical cross-linking

- H-bonded hydrogel can be obtained by lowering the pH of aqueous solution of polymers carrying carboxyl groups.

- Examples of such hydrogel is a hydrogen-bound CMC (carboxymethyl cellulose) network formed by dispersing CMC into 0.1M HCl. - The mechanism involves replacing the sodium in CMC with hydrogen in the acid solution to promote hydrogen bonding.

- The hydrogenbonds induce a decrease of CMC solubility in water and result in the formation of an elastic hydrogel.

- Transactions of the Materials Research Society of Japan, Vol 32, No 332, 713-716 27

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking Grafting of monomers on the backbone of the polymers or

Properties

The use of a cross-linking agent to link two polymer chains

The cross-linking of natural and synthetic polymers can be achieved through the reaction of their functional groups

- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking

Using chemical cross-linkers

Methods

Grafting monomers on preformed polymer Radiation cross-linking

- Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips. Hydrogels: Methods of Preparation, Characterisation and Applications. 2011, InTechOpen.

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III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking For example: preparation of Carageenan/GA hydrogels

- Glutaraldehyde (GA) with a certain concentration (1-5 wt%) was prepared by diluting GA 25 wt% GA solution) with distilled water. The carrageenan film was immersed in GA-water mixture for 2 min.

- The surface of film was wiped with filter cloth and then cured at 1100C in oven for 25 min. The crosslinked film was soaked in water with stirring for 1 min and then in ethanol for 4 hr to remove unreacted GA. The wet hydrogels were dried at room temperature to a constant weight.

- Engineering Journal, Volume 17, Issue 3, 2013, ISSN 0125-8281. DOI:10.4186/ej.2013.17.3.57 30

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.1. Preparations of hydrogels 3.1.2. Chemical cross-linking For example: preparation of Carageenan/GA hydrogels

- Engineering Journal, Volume 17, Issue 3, 2013, ISSN 0125-8281. DOI:10.4186/ej.2013.17.3.57 31

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels The samples of hydrogels were immersed in a solution of drugs.

General methods

The swollen hydrogels loaded with drug were placed in a vacuum oven and dried under vacuum at certain temperature.

The loading amount of drug in the hydrogels was specified from the decrease in the concentration of drug solution using UV spectrophotometer.

The loading efficiency of hydrogels was calculated as the ratio of the final to the initial drug concentration 32

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels  Powdered samples of Pc-poly(NaAA-

co-AAm), hydrogel (1 g ± 0.0001), were accurately weighted and immersed in an alkaline solution of ibuprofen (IBU, 0.54 g dissolved in 50 mL distilled water) at 0˚C for 25 h.

Ibuprofen (IBU)

 Mohammad Sadeghi

 The swollen hydrogels loaded with

drug were placed in a vacuum oven and dried under vacuum at 37˚C.

- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 33

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels  The loading amount of drug in the

hydrogels was calculated from the decrease in the concentration of the IBU solution which was determined using a UV spectrophotometer.

Ibuprofen (IBU)

 Mohammad Sadeghi

 The loading efficiency of the Pectin-

based hydrogels was calculated as the ratio of the final to the initial IBU concentration.

- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 34

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels

Ibuprofen (IBU)

ï‚— Mohammad Sadeghi

- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005 35

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels  PEC/PAM and PEC/DEAMA hydrogels

- drug conjugate was prepared by desolving different weights of drug

Chlorotetracycline (CTC) - Antibiotic

(Chlortetracycline HCL as model drugs) (0.2, 0.3, 0.35, 0.4 and 0.5 mg) each in

distilled water to prepare (0.2, 0.3, 0.35,

 Faten I. Abou El Fadl

and Nabila A. Maziad

0.4 and 0.5 mg/ml) drug concentrations.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 36

III. THE SYSTHESIS OF HYDROGELS, THE WAYS TO LOAD DRUGS INTO HYDROGELS AND THE RELEASE OF DRUGS FROM HYDROGELS

3.2. Preparation of drug-loaded hydrogels  The dry polymer blends with known

weight 0.1 g), were soaked into the drug solutions at room temperature until the complete adsorption for 72 h.  Then the amount of drug adsorbed

Chlorotetracycline (CTC) - Antibiotic

onto polymer hydrogels at different  Faten I. Abou El Fadl compositions was determined by and Nabila A. Maziad using UV–Vis spectrophotometer at identical drug absorbance wavelength.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 37

III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.1. Mechanism

ï‚— The mechanism of drug release consists of the following phenomena:

1- Exterior diffusion, 2- Interior diffusion, 3- Desorption, 4- Chemical reactions, 5- Matrix erosion.

- Roman ZARZYCKI, Zofia MODRZEJEWSKA and Katarzyna NAWROTEK. Ecological Chemistry and Engineering, Vol.17, No.2, 2010.

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.1. Mechanism

 The release of water-soluble drug, entrapped in a

hydrogels, occur only after water penetrates the network to swell the polymer and dissolve the drug, followed by diffusion along the aqueous pathways to the surface of the device.  The release of drug is closely related to the swelling

characteristics of the hydrogels, which in turn, is a key function of chemical architecture of the hydrogels.

- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5 39

III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.2. Experiments

Placing dried and loaded sample in definite volume of different pH medium at 370C. At specific time intervals, certain aliquots of sample was withdrawn and determined by UV spectrophotometer.

Released drug (%) = Rt/L x 100 - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.2. Experiments

Baljit Singh, Ritu Bala and Nirmala Chauhan  Tetracycline hydrochloride-loaded Psy-cl-poly(AAc) hydrogels were immersed in different pH buffer including distilled water, pH 2.2 and pH 7.4.  After 30 min, aliquots were got and measured spectrophotometrically at λmax = 357, 358 and 362 nm.

- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.2. Experiments

 At higher pH, amount of released drug was higher and

quicker.

- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.2. Experiments

ï‚— Faten I. Abou El Fadl and Nabila A. Maziad

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2.

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.3. Various environmental stimuli for triggering drug release from reponsive hydrogels

- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025

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III. THE SYSTHESIS OF HYDROGELS, WAYS TO LOAD DRUGS INTO HYDROGELS AND RELEASE DRUGS

3.3. Release drug from hydrogels 3.3. Various environmental stimuli for triggering drug release from reponsive hydrogels

- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.1. Analysis of structures and characteristics  There are a number of methods of analysis of

hydrogels structure which depends on the preparation, aims to define charaterization parameters.  Susana Simões, Ana Figueiras, and Francisco Veiga summaried all of techniques of measurement, as table below:

- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.1. Analysis of structures and characteristics

- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.1. Analysis of structures and characteristics

- Journal of Biomaterials and Nanobiotechnology, 2012, 3, 185-199 . DOI:10.4236/jbnb.2012.32025

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures

Swelling study IR Spectroscopic analysis Analysis of Structure

Ultraviolet (UV) analysis Thermogravimetric analysis (TGA) 49

IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.1. Swelling studies

Target

- Calculate percentage of the total water uptake

Define some coefficients for measuring swelling kinetics

- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2

50

IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.2. IR Spectroscopic analysis

Purpose

Specify functional groups at specific wavenumbers

Confirm the interaction between polymers in hydrogels

- J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.2. IR Spectroscopic analysis

The appearance of new peaks indicates the stretching of some functional groups when creating hydrogels.

- Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.3. Ultravillet (UV) analysis

Determining the amount of drug adsorbed onto hydrogels (effective adsorption) Goals Specifying the quantity of drug released from hydrogels in different media - J Mater Sci: Mater Med (2008) 19:2771–2780. DOI 10.1007/s10856-008-3406-5.

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 - Journal of Biomaterials and Nanobiotechnology, 2011, 2, 36-40. DOI:10.4236/jbnb.2011.21005

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.3. Ultravillet (UV) analysis

- N.A. Peppas et al. / Journal of Controlled Release, 62 (1999) 81–87

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IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.4. Thermogravimetric analysis (TGA)

Studying thermostability of hydrogels Objectives

Measuring the compositions of hydrogels

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 55

IV. MEANS OF ANALYSIS OF STRUCTURES AND EFFECTIVE LOADINGS

4.2. Focussing on analysis of structures 4.2.4. Thermogravimetric analysis (TGA)

- J Radioanal Nucl Chem . DOI 10.1007/s10967-014-3514-2 56

V. POSIBILITIES OF APPLICATION

5.1. View of applications  In recent years, there has been remarkable process in the

development of clinically applied hydrogels.  Since 1960, the copolymers of 2-(HEMA) and ethylene

dimethacrylate have been applied for their use in contact lens, urinary catheters, wound dressing and surgical gloves, etc.  After that, development of clinically applied hydrogels

has attracted research regards.

- Journal of Materials Chemistry B, 2014, 2, 147-166.

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V. POSIBILITIES OF APPLICATION

5.1. View of applications

- Journal of Materials Chemistry B, 2014, 2, 147-166.

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V. POSIBILITIES OF APPLICATION

5.1. View of applications

- Journal of Materials Chemistry B, 2014, 2, 147-166.

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V. POSIBILITIES OF APPLICATION

5.2. Some of specific applications  Implanting degradable insulin loaded-poly(NIPAAm-

co-Dex-lactateHEMA) hydrogels to rat’s conjunctiva for treating diabetic retinopathy.

- G.P. Misra et al. / Biomaterials 30 (2009) 6541–6547

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V. POSIBILITIES OF APPLICATION

5.2. Some of specific applications  Results of research demonstrated that both hydrogels and

their degradation products were non-toxic to cultured R28 retinal cells, and accordingly the hydrogels have potential for in vivo implantation.  None of inflammation or morphological changes in eyes implanted insulin loaded hydrogels.

- G.P. Misra et al. / Biomaterials 30 (2009) 6541–6547

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V. POSIBILITIES OF APPLICATION

5.2. Some of specific applications  Investigating starPEG-heparin-based hydrogels loaded by some Growth Factors (GFs): bFGF and EGF.  Applying to treat acute kidney injury on mice.

 The results confirm possitive indication to ultilizing hydrogels for GFs delivery.

- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255

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V. POSIBILITIES OF APPLICATION

5.2. Some of specific applications

- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255

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V. POSIBILITIES OF APPLICATION

5.2. Some of specific applications  No visual signs of inflammation for both the control

and the GFs treated mice.  The hydrogels alone did not induce treatment

efficency.  There was the difference of proliferation between the

left injected GF and the right non-injected GF kidney.

- M.V. Tsurkan et al. / Journal of Controlled Release 167 (2013) 248–255

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V. POSIBILITIES OF APPLICATION

5.3. Some drawbacks of hydrogels in DDSs May release toxic subtances Low mechanical strength ->limits load bearing

Hydrogels Moist -> sterility, shipping, packing Some risks of infection, delayed wound healing.

- Journal of Materials Chemistry B, 2014, 2, 147-166.

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VI. SUMMARY

 Hydrogels are considered one of drug delivery

systems which has crucial position in medical applications.  There has been a great number of researches related to hydrogels, which aims to apply to target diseases on the majority of human body.  Besides advantages, hydrogels also have some drawbacks requiring the advance of design of

hydrogels’ properties.

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